Those are Presidents that had the title " President of the Congress of the Confederation" or alternatively "The president of the United States in Congress Assembled."
He was elected by the delegates of the congress, to preside over the meetings of congress. There was no salary, and a largely ceremonial title. Its about as much fun and useful as being the Vice President and moderating the senate.
I think it would be a intellectually dishonest to suggest these were the first Presidents of the United States.